Without a shot being fired, notorious drug kingpin and international fugitive Joaquin "El Chapo" Guzman was arrested by Mexican security forces in Mazatlan, Mexico last weekend. The man who lived his life profiting from drug trafficking, human misery, corrupting public officials and undermining the rule of law is now behind bars.

This is a tremendous victory for the citizens of Mexico and the United States. Americans are demanding his extradition. Our friends and neighbors to the south, from all appearances, are moving towards prosecution within their own country. That debate will continue, but we must not lose sight of the most important aspect of this victory; the strong relationship between our nations that was critical to this success.

The joint capture of the world’s most infamous criminal cartel chief represents a seismic shift in U.S.-Mexico relations from the low point in 1985 when American undercover DEA agent Enrique “Kiki” Camarena was abducted, tortured and bludgeoned to death while working in Mexico. In the decades following Camarena’s death, cross-border relations in the drug war were crippled by mistrust on both sides.

U.S. officials watched in dismay as top Mexican anti-drug officials were arrested for taking payoffs and aiding and abetting the drug lords. Mexican authorities despaired that their U.S. counterparts had little understanding of the terror and fear that ruled their lives under the threats of the mafia bosses. In fact, it is estimated that up to 60,000 Mexicans -- many of them innocent bystanders, honest public officials and courageous journalists -- died from drug-related violence between 2006 and 2012, the peak years in the drug war.

Apprehending Guzman was no easy task. He had evaded arrest for nearly 13 years. I know how difficult the law enforcement effort was because I spent nearly 10 years of my own life endeavoring to apprehend El Chapo. During most of that hunt I served as the national chief of the U. S. Border Patrol, and Deputy Commissioner and Acting Commissioner of U.S. Customs and Border Protection. Guzman’s criminal organization was and is relentless in its ruthless and criminal pursuits. His Sinaloa cartel is believed to be responsible for about 25 percent of all illegal drugs that cross the Mexican border into the United States.

I saw and lived through the evolution and development of trust, confidence, and collaboration between us and our Mexican counterparts. Our two nations have worked long and hard to get to the partnership that we now enjoy. Sharing intelligence, following leads, and working together are now our recognized and expected way of conducting business.

This process, the very ability to prosecute a tactical operation of the kind that took Guzman down, is the fundamental difference between success and failure and why Mexican authorities were successful. Mexico's former President Felipe Calderon was committed to breaking the cycle of cartel violence. Current President Enrique Pena Nieto has redoubled that commitment by focusing on a comprehensive strategy to eradicate the cartels by improving the Mexican economy, its schools, its infrastructure, and its law enforcement capability. This strategy is working, and we saw it first-hand when Mexican Marines walked out of that Mazatlan apartment with “El Chapo” Guzman in handcuffs.

I believe the bond the United States and Mexico now share will continue to strengthen in the years to come. Our governments are united in the concern we share for the safety of our citizens. For too long, too many lived in fear of Guzman and his organization.

But, while Guzman is under arrest, others remain at large. These organizations operate like Hydra -- as soon as one head is taken out, another will fight to emerge.

The value of our relationship with our neighbors to the south will continue to increase as our nations continue to fight the now-weakened and more vulnerable Sinaloa Cartel and the others remaining. But neither side can let down its guard. Much remains to be done. The war has not yet been won.

But, by working to ensure this partnership continues to evolve, all of our citizens will continue to reap the benefits of safer borders, safer communities, and a more prosperous future.

David Aguilar is former Acting Commissioner of U.S. Customs and Border Protection and National Chief of the Border Patrol. He currently is a partner in Global Security and Intelligence Strategies, an international consulting firm.